Research Progress on Key Technologies of Grease Lubrication for High-Performance Rolling Bearings

Abstract

Rolling bearings are key components in mechanical transmissions, and grease serves as the core medium ensuring their stable operation. It reduces friction and wear, dissipates heat, seals against dust, and directly extends bearing service life. This paper systematically reviews five core areas of rolling bearing grease: rheological property evolution, lubrication theory development, service life research, experimental technologies, and innovations in materials and structure. Rheological studies confirm that grease is a non-Newtonian fluid whose thixotropy and viscoelasticity dominate oil film formation, friction resistance, and working condition adaptability; the Herschel-Bulkley model accurately describes its rheological behavior, and low apparent viscosity at specific shear rates helps reduce bearing vibration and noise. Lubrication theory has evolved from classic elastohydrodynamic lubrication (EHL) to thermal EHL (TEHL) and micro-EHL, where the rheological index significantly affects film thickness and pressure distribution, and increased axial load improves lubrication stability in high-speed bearings. Life research reveals that oxidation is the dominant failure factor of lithium-based grease, a proper thickener formula markedly prolongs bearing fatigue life, and higher energy density or heat transfer entropy density drastically shortens grease life. Experimental technologies have advanced from basic performance tests to precise methods including high-temperature high-speed simulation, in-situ oil film thickness measurement, and electrochemical characterization, enabling quantification of the relationships between speed, load, temperature, and lubrication status. Material innovation focuses on bio-based greases and nano-additives; multi-walled carbon nanotubes and Ti₃C₂ MXenes significantly enhance tribological performance. Structural optimization via seal design and oil return schemes effectively mitigates grease leakage. China has achieved breakthroughs in noise reduction and vibration resistance for bearing greases, but gaps remain in R&D of key materials such as high-performance base oils, special thickeners, and novel additives compared with advanced international levels. The results provide theoretical and practical references for breaking technical barriers in high-end lubricants, optimizing bearing lubrication design, promoting cost reduction and efficiency improvement in manufacturing, and achieving independent control of high-end equipment.